Depletion mode junction field effect transistors (JFETs) are efficient semiconductor structures, especially for high-voltage switching applications. However, depletion mode JFETs require a negative gate-to-source potential to turn off. Accordingly, when a system incorporating a JFET is first turned on, the depletion mode JFET is also on, causing undesirable high current to flow in most applications.
An enhancement mode metal-oxide-semiconductor field effect transistor (MOSFET), on the other hand, requires a positive voltage to turn on. Therefore, the MOSFET, being a normally off device, does not typically exhibit high current flows in most applications upon start-up. However, MOSFETs are generally not normally the most cost-efficient devices for high voltage (>100V) applications.
Accordingly, there remains a need for semiconductor device having C) improved high-voltage switching characteristics in combination with low current flow characteristics at start-up and no requirement for negative gate bias.